Past studies have suggested that high-fructose corn syrup and other sweeteners like table sugar are nutritionally identical. But the authors of a new study in Pharmacology, Biochemistry and Behavior say that's not so.

When it comes to weight gain, the study found, rats with access to high-fructose corn syrup gained significantly more weight than those with access to table sugar, even when their overall caloric intake was the same.

In addition to causing significant weight gain in lab animals, long-term consumption of high-fructose corn syrup also led to abnormal increases in body fat, especially in the abdomen, and a rise in circulating blood fats called triglycerides. The researchers say the work sheds light on the factors contributing to obesity trends in the United States.

"Some people have claimed that high-fructose corn syrup is no different than other sweeteners when it comes to weight gain and obesity, but our results make it clear that this just isn't true, at least under the conditions of our tests," said psychology professor Bart Hoebel, who specializes in the neuroscience of appetite, weight and sugar addiction.

"When rats are drinking high-fructose corn syrup at levels well below those in soda pop, they're becoming obese -- every single one, across the board. Even when rats are fed a high-fat diet, you don't see this; they don't all gain extra weight."

In the first of two experiments, researchers found that male rats given water sweetened with high-fructose corn syrup in addition to a standard diet of rat chow gained much more weight than male rats that received water sweetened with table sugar, or sucrose, in conjunction with the standard diet. The concentration of sugar in the sucrose solution was the same as is found in some commercial soft drinks, while the high-fructose corn syrup solution was half as concentrated as most sodas.

The second experiment -- the first long-term study of the effects of high-fructose corn syrup consumption on obesity in lab animals -- monitored weight gain, body fat and triglyceride levels in rats with access to high-fructose corn syrup over a period of six months.

Compared to animals eating only rat chow, rats on a diet rich in high-fructose corn syrup showed characteristic signs of a dangerous condition known in humans as the metabolic syndrome, including abnormal weight gain, significant increases in circulating triglycerides and augmented fat deposition, especially visceral fat around the belly. Male rats in particular ballooned in size: Animals with access to high-fructose corn syrup gained 48 percent more weight than those eating a normal diet. In humans, this would be equivalent to a 200-pound man gaining 96 pounds.

High-fructose corn syrup and sucrose are both compounds that contain the simple sugars fructose and glucose, but there at least two clear differences between them. First, sucrose is composed of equal amounts of the two simple sugars -- it is 50 percent fructose and 50 percent glucose -- but the typical high-fructose corn syrup used in this study features a slightly imbalanced ratio, containing 55 percent fructose and 42 percent glucose.

Larger sugar molecules called higher saccharides make up the remaining 3 percent of the sweetener. Second, as a result of the manufacturing process for high-fructose corn syrup, the fructose molecules in the sweetener are free and unbound, ready for absorption and utilization. In contrast, every fructose molecule in sucrose that comes from cane sugar or beet sugar is bound to a corresponding glucose molecule and must go through an extra metabolic step before it can be utilized.

This creates a fascinating puzzle. The rats in the Princeton study became obese by drinking high-fructose corn syrup, but not by drinking sucrose. The critical differences in appetite, metabolism and gene expression that underlie this phenomenon are yet to be discovered, but may relate to the fact that excess fructose is being metabolized to produce fat, while glucose is largely being processed for energy or stored as a carbohydrate, called glycogen, in the liver and muscles.

"Our findings lend support to the theory that the excessive consumption of high-fructose corn syrup found in many beverages may be an important factor in the obesity epidemic," Avena said.

The new research complements previous work led by Hoebel and Avena demonstrating that sucrose can be addictive, having effects on the brain similar to some drugs of abuse.

Comments

Princeton researchers used grossly exaggerated intake levels and incorrectly suggested their results could have significant meaning for humans in their recent rat study on obesity and high fructose corn syrup.
Translating the study’s reported rat intakes to human proportions, the calories gained from high fructose corn syrup would be equivalent to about 3000 kcal/day all from that single source. In comparison, adult humans consume about 2,000 calories per day from all dietary sources. Such intake levels would be the equivalent of humans drinking a total of 20 cans of 12 ounce sodas per day - a highly unrealistic amount. Moreover, the researchers concluded that the rats gained more weight from high fructose corn syrup than they would have from sugar, yet they failed to provide sucrose controls for part of the study’s short-term experiments and no sucrose controls whatsoever were present in any of the long-term experiments.
No metabolic effects have been found in studies that compare sugar and high fructose corn syrup consumption in humans.
Audrae Erickson, Corn Refiners Association

I'm a grad student in bioinformatics and computational biology with no affiliation to anyone involved in the study, or to the lobbying industry, whom I assume most people will inherently distrust (sorry Audrae). Nevertheless, this study and the coverage it's receiving have me extremely upset as a scientist because even a cursory glance at the actual journal article reveals there to be far more problems than just the one listed above. I've already ranted in two other blog comments elsewhere so I won't do it again here. Here's Fig. 1 from the study: http://imgur.com/2vNNJ and the longer of my two rants: bit.ly/btDbfs
To clarify, I'm not saying that high doses of HFCS aren't bad for you; I think it's been very clearly established that they are. All I'm saying is that the article does not support the claim that equivalent levels of sucrose would be any less bad for you.

A new study released Thursday suggests sodas sweetened with high fructose corn syrup may contribute to the development of diabetes. The study from researchers at Rutgers University, shows sodas sweetened with high fructose corn syrup contain high levels of compounds that previous research suggests may play a role in the development of diabetes. Especially when consumed in large amounts.

Funny that you would jump on someone for posting "A new study" claiming that this is a site for science and yet back up a post by someone claiming that the idea of high fructose corn syrup causing obesity is nonsense simply because he used to be obese and never drank the stuff, an UTTERLY ridiculous assertion. Don't get me wrong, you were absolutely right to question the first post but the fact that you didn't follow the same standards with the 2nd post clearly shows your alignment in regards to this subject. Bash those who question HFCS and back up those who think HFCS is just as healthy as other sugars. Science has nothing to do with it , it's just a word that you use to discredit those who have a different opinion than your own.

I wouldn't trust a single thing you say at this point and I would strongly urge others to do the same. You couldn't have possibly made your intentions any more clear. If your true interest were truly the findings of science, you would have laughed the 2nd guy off the board as his assertion is what you would expect from a 6 year old in his first day of science class.

Puncturing myths is not selling out. Selling out involves, you know, selling, and no one at Big HFCS or Big Sugar or whatever gives the site any money. A few years from now it may be settled science that HFCS is worse than sugar, it also may be settled science that HFCS is better than sugar. Right now, though, the sugar industry is engaged in a marketing campaign trying to imply their bleached white processed product is superior to HFCS and that is not true.